Optimization of water huff-n-puff injection in Chang 8 tight oil reservoir by Taguchi method

Abstract

Huff-n-puff water injection has been considered a cost-effective method to improve oil recovery for multiple fractured horizontal wells in tight oil reservoirs. However, the performance of this technique depends heavily on the operational parameters and needs to be optimized. In the study, Taguchi L9 orthogonal array was employed to optimize the parameters to have a synergistic effect on well oil production. Both signal-to-noise ratio and main effect results suggest that the influences of the factors on the well oil production were ranked by water injection volume > water injection rate > soaking time > liquid production rate, and the most efficient combination of parameters were 5000 m3 water injection volume, 200 m3/d injection rate, 30 m3/d liquid production rate, and 50 days soaking time. Moreover, Analysis of Variance was used to examine the contribution rate of each factor for the well oil production. It was indicated that the water injection volume was the most influential parameter at 85.29% contribution, followed by water injection rate at 10.85%, soaking time at 1.78%, and liquid production rate at 1.56%. Such findings provide insights into the optimization of oil recovery for the water huff-n-puff injection operations.